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Hybrid Primer?

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JAL3

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I have followed with some interest the thread on the future of hybrids. THis is an area about which I know little but am interested.

Can anyone point to a good introductory thread, article or primer on the subject?

Pros and cons of various setups?

Pitfalls and common mistakes?

Beginner's guide to GSE?

Anything else a noob ought to know?
 

billspad

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I have followed with some interest the thread on the future of hybrids. THis is an area about which I know little but am interested.

Can anyone point to a good introductory thread, article or primer on the subject?

Pros and cons of various setups?

Pitfalls and common mistakes?

Beginner's guide to GSE?

Anything else a noob ought to know?
Try this.

Hypertek has the most expensive GSE. You can make your own for the rest of them with parts from McMaster.

Get a vent detector.

Use an accelerometer type altimeter.
 
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Try this.

Hypertek has the most expensive GSE. You can make your own for the rest of them with parts from McMaster.

Get a vent detector.

Use an accelerometer type altimeter.
Hi,
At one time, certain types of accelerometer-type altimeters would be confused by the thrust of a hybrid motor. Hybrid motors tend to have a high-frequency pulse-type combustion. This pulse-type combustion could interfere with the sampling rate of the accelerometer and lead to altimiter errors. I've used baro-based altimeters (PerfectFlite MAWD and HiAlt 45k) with SkyRipper motors and I've never had a problem. I would tend to recommend barometric-based altimeters. Bill probably has a good reason why an accelerometer would be better. Maybe he will let us know.
Floyd
 

billspad

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Hi,
At one time, certain types of accelerometer-type altimeters would be confused by the thrust of a hybrid motor. Hybrid motors tend to have a high-frequency pulse-type combustion. This pulse-type combustion could interfere with the sampling rate of the accelerometer and lead to altimiter errors. I've used baro-based altimeters (PerfectFlite MAWD and HiAlt 45k) with SkyRipper motors and I've never had a problem. I would tend to recommend barometric-based altimeters. Bill probably has a good reason why an accelerometer would be better. Maybe he will let us know.
Floyd
I use Pico altimeters and haven't had any error problems. I prefer them to baro because the arm at a low altituded. I had one save a rocket that get to less than 75' because of a strangely underpowered motor.
 

Pantherjon

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This is all interesting! I very much want to 'dabble' some in hybrids! We have quite a few guys doing hybrids at my club and they have the GSE..They just leave me in the dust when they start 'getting into it' talking about hybrids!:roll: I know the fuel grains can be made out of virtually anything that can burn..Our prefect 'Captain' Jack, has shown me grains he has made from 2" PVC pipe!

Will have to explore the flyhybrids site(and others) to get 'up to speed' on this!
 

bobkrech

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Hi,
At one time, certain types of accelerometer-type altimeters would be confused by the thrust of a hybrid motor. Hybrid motors tend to have a high-frequency pulse-type combustion. This pulse-type combustion could interfere with the sampling rate of the accelerometer and lead to altimiter errors. I've used baro-based altimeters (PerfectFlite MAWD and HiAlt 45k) with SkyRipper motors and I've never had a problem. I would tend to recommend barometric-based altimeters. Bill probably has a good reason why an accelerometer would be better. Maybe he will let us know.
Floyd
A problem that existed several years ago in sevral accelerometer based altimeters is that they employed a poor launch detection algorithm. The vibrations in larger hybrids can be severe and the negative g-peaks of the vibrations can exceed the positive g peak of the launch. The simplest launch detection algorithms simply looked for positive g's for 0.2 to 0.5 seconds and if a single point was negative, reset the timer. This could have been averted by filtering the accelerometer output and was fixed by adding a digital filter to the launch detections algorithm. Another fix was to use a break-wire which will provide a positive launch detection.

I believe the major manufacturers have all corrected their altimeters by now, and it's no longer a problem.

Bob
 

troj

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FWIW, while stock HyperTEK GSE is expensive, the only part you need from CTI is the fill stem assembly. The other bits can be assembled yourself, without much difficulty.

For any hybrid, you want your fill valve to use a relay, with a battery at the pad, especially when flying in warmer temperatures. A full nitrous cylinder will put a lot of pressure on the solenoid, and trying to open that solenoid via current over 100+ feet of extension cord is a recipe for frustration.

Put your battery by the solenoid, and a lot of grief will disappear.

I'd also suggest that your first foray into flying hybrids be with the assistance of someone who has done it before. You'll learn a lot that will save you a tremendous amount of grief.

-Kevin
(HyperTEK, RATTWorks, Sky Ripper)
 
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